Downregulation of Ubiquitin-Specific Protease 15 (USP15) Does Not Provide Therapeutic Benefit in Experimental Mesial Temporal Lobe Epilepsy

Structural epilepsies display complex immune activation signatures. However, it is unclear which neuroinflammatory pathways drive pathobiology. Transcriptome studies of brain resections from mesial temporal lobe epilepsy (mTLE) patients revealed a dysregulation of transforming growth factor β, interferon α/β, and nuclear factor erythroid 2-related factor 2 pathways. Since these pathways are regulated by ubiquitin-specific proteases (USP), in particular USP15, we hypothesized that USP15 blockade may provide therapeutic relief in treatment-resistant epilepsies. For validation, transgenic mice which either constitutively or inducibly lack Usp15 gene expression underwent intrahippocampal kainate injections to induce mTLE. We show that the severity of status epilepticus is unaltered in mice constitutively lacking Usp15 compared to wild types. Cell death, reactive gliosis, and changes in the inflammatory transcriptome were pronounced at 4 days after kainate injection. However, these brain inflammation signatures did not differ between genotypes. Likewise, induced deletion of Usp15 in chronic epilepsy did not affect seizure generation, cell death, gliosis, or the transcriptome. Concordantly, siRNA-mediated knockdown of Usp15 in a microglial cell line did not impact inflammatory responses in the form of cytokine release. Our data show that a lack of USP15 is insufficient to modulate the expression of relevant neuroinflammatory pathways in an mTLE mouse model and do not support targeting USP15 as a therapeutic approach for pharmacoresistant epilepsy.

An orally available small molecule that targets soluble TNF to deliver anti-TNF biologic-like efficacy in rheumatoid arthritis

Tumor necrosis factor (TNF) is a pleiotropic cytokine belonging to a family of trimeric proteins with both proinflammatory and immunoregulatory functions. TNF is a key mediator in autoimmune diseases and during the last couple of decades several biologic drugs have delivered new therapeutic options for patients suffering from chronic autoimmune diseases such as rheumatoid arthritis and chronic inflammatory bowel disease. Attempts to design small molecule therapies directed to this cytokine have not led to approved products yet. Here we report the discovery and development of a potent small molecule inhibitor of TNF that was recently moved into phase 1 clinical trials. The molecule, SAR441566, stabilizes an asymmetrical form of the soluble TNF trimer, compromises downstream signaling and inhibits the functions of TNF in vitro and in vivo. With SAR441566 being studied in healthy volunteers we hope to deliver a more convenient orally bioavailable and effective treatment option for patients suffering with chronic autoimmune diseases compared to established biologic drugs targeting TNF.

Planning experiments: Updated guidance on experimental design and analysis and their reporting III

Scientists who plan to publish in British Journal of Pharmacology (BJP) must read this article before undertaking a study. This editorial provides guidance for the design of experiments. We have published previously two guidance documents on experimental design and analysis (Curtis et al., 2015; Curtis et al., 2018). This update clarifies and simplifies the requirements on design and analysis for BJP manuscripts. This editorial also details updated requirements following an audit and discussion on best practice by the BJP editorial board. Explanations for the requirements are provided in the previous articles. Here, we address new issues that have arisen in the course of handling manuscripts and emphasise three aspects of design that continue to present the greatest challenge to authors: randomisation, blinded analysis and balance of group sizes.

COVID-19 and Pregnancy: A Prospective Descriptive Study from a Tertiary Hospital in Nigeria

BACKGROUND

It is known that pregnant women are more susceptible to viral infectious diseases, with an attendant risk of adverse foetal and maternal outcomes. The objective of this descriptive study is to evaluate the epidemiologic and clinical pattern, as well as the obstetric and COVID-19 outcome among pregnant women seen at a tertiary hospital in Southern, Nigeria.

METHODS

This was a descriptive prospective study of all pregnant women seen and diagnosed with COVID-19 based on positive RT-PCR for SARS-COV-2, at the University of Port Harcourt Teaching Hospital, Port Harcourt, Rivers State, Nigeria from March 2020 to August 2020.

RESULTS

Seven (5.2%) pregnant patients were diagnosed with COVID-19 out of 134 patients. The common presenting symptoms were fever 4(57.1%), Productive cough 3 (42.9%), shortness of breath 3 (42.9%), myalgia 3 (42.9%), rhinorrhoea 3 (42.9%), and anosmia 3 (42.9%). The majority (85.7%) of patients were in the second and third trimesters at diagnosis. All deliveries occurred at term, with a mean gestational age of 38±0.82 weeks. Four patients (57.1%) had caesarean section (CS) deliveries for obstetric indications. No adverse outcomes were recorded for mothers and babies with birth weight ranging from 2.5 to 3.5 Kg. No case fatality was recorded.

CONCLUSION

In this study, pregnant women with COVID-19 did not have adverse maternal and foetal outcome. The pattern of symptoms and the presence of severe disease also did not differ from what is observed in the general non-pregnant population. The impact of COVID-19 on pregnancy is less severe when compared to other high consequence viral infectious diseases.

The Chemical Synthesis of Knob Domain Antibody Fragments

Cysteine-rich knob domains found in the ultralong complementarity determining regions of a subset of bovine antibodies are capable of functioning autonomously as 3-6 kDa peptides. While they can be expressed recombinantly in cellular systems, in this paper we show that knob domains are also readily amenable to a chemical synthesis, with a co-crystal structure of a chemically synthesized knob domain in complex with an antigen showing structural equivalence to the biological product. For drug discovery, following the immunization of cattle, knob domain peptides can be synthesized directly from antibody sequence data, combining the power and diversity of the bovine immune repertoire with the ability to rapidly incorporate nonbiological modifications. We demonstrate that, through rational design with non-natural amino acids, a paratope diversity can be massively expanded, in this case improving the efficacy of an allosteric peptide. As a potential route to further improve stability, we also performed head-to-tail cyclizations, exploiting the proximity of the N and C termini to synthesize functional, fully cyclic antibody fragments. Lastly, we highlight the stability of knob domains in plasma and, through pharmacokinetic studies, use palmitoylation as a route to extend the plasma half-life of knob domains in vivo. This study presents an antibody-derived medicinal chemistry platform, with protocols for solid-phase synthesis of knob domains, together with the characterization of their molecular structures, in vitro pharmacology, and pharmacokinetics.

An Analysis of Clostridium difficile Environmental Contamination During and After Treatment for C difficile Infection

Background

Lower Clostridium difficile spore counts in feces from C difficile infection (CDI) patients treated with fidaxomicin versus vancomycin have been observed. We aimed to determine whether environmental contamination is lower in patients treated with fidaxomicin compared with those treated with vancomycin/metronidazole.

Methods

The CDI cases were recruited at 4 UK hospitals (Leeds, Bradford, and London [2 centers]). Environmental samples (5 room sites) were taken pretreatment and at 2–3, 4–5, 6–8, and 9–12 days of treatment, end of treatment (EOT), and post-EOT. Fecal samples were collected at diagnosis and as often as produced thereafter. Swabs/feces were cultured for C difficile; percentage of C difficile-positive samples and C difficile bioburden were compared between different treatment arms at each time point.

Results

Pre-EOT (n = 244), there was a significant reduction in environmental contamination (≥1 site positive) around fidaxomicin versus vancomycin/metronidazole recipients at days 4–5 (30% vs 50% recipients, P = .04) and at days 9–12 (22% vs 49%, P = .005). This trend was consistently seen at all other timepoints, but it was not statistically significant. No differences were seen between treatment groups post-EOT (n = 76). Fidaxomicin-associated fecal positivity rates and colony counts were consistently lower than those for vancomycin/metronidazole from days 4 to 5 of treatment (including post-EOT); however, the only significant difference was in positivity rate at days 9–12 (15% vs 55%, P = .03).

Conclusions

There were significant reductions in C difficile recovery from both feces and the environment around fidaxomicin versus vancomycin/metronidazole recipients. Therefore, fidaxomicin treatment may lower the C difficile transmission risk by reducing excretion and environmental contamination.

Cross-sectional study of the prevalence, causes and management of hospital-onset diarrhoea

BACKGROUND

The National Health Service in England advises hospitals collect data on hospital-onset diarrhoea (HOD). Contemporaneous data on HOD are lacking.

AIM

To investigate prevalence, aetiology and management of HOD on medical, surgical and elderly-care wards.

METHODS

A cross-sectional study in a volunteer sample of UK hospitals, which collected data on one winter and one summer day in 2016. Patients admitted ≥72 h were screened for HOD (definition: ≥2 episodes of Bristol Stool Type 5-7 the day before the study, with diarrhoea onset >48 h after admission). Data on HOD aetiology and management were collected prospectively.

FINDINGS

Data were collected on 141 wards in 32 hospitals (16 acute, 16 teaching). Point-prevalence of HOD was 4.5% (230/5142 patients; 95% confidence interval (CI) 3.9-5.0%). Teaching hospital HOD prevalence (5.9%, 95% CI 5.1-6.9%) was twice that of acute hospitals (2.8%, 95% CI 2.1-3.5%; odds ratio 2.2, 95% CI 1.7-3.0). At least one potential cause was identified in 222/230 patients (97%): 107 (47%) had a relevant underlying condition, 125 (54%) were taking antimicrobials, and 195 (85%) other medication known to cause diarrhoea. Nine of 75 tested patients were Clostridium difficile toxin positive (4%). Eighty (35%) patients had a documented medical assessment of diarrhoea. Documentation of HOD in medical notes correlated with testing for C. difficile (78% of those tested vs 38% not tested, P<0.001). One-hundred and forty-four (63%) patients were not isolated following diarrhoea onset.

CONCLUSION

HOD is a prevalent symptom affecting thousands of patients across the UK health system each day. Most patients had multiple potential causes of HOD, mainly iatrogenic, but only a third had medical assessment. Most were not tested for C. difficile and were not isolated.

Cost-effectiveness of outpatient parenteral antibiotic therapy: a simulation modelling approach

Objectives

In the UK, patients who require intravenous antimicrobial (IVA) treatment may receive this in the community through outpatient parenteral antimicrobial therapy (OPAT) services. Services include: IVA administration at a hospital outpatient clinic (HO); IVA administration at home by a general nurse (GN) or a specialist nurse (SN); or patient self-administered (SA) IVA administration following training. There is uncertainty regarding which OPAT services represent value for money; this study aimed to estimate their cost-effectiveness.

Methods

A cost-effectiveness decision-analytic model was developed using a simulation technique utilizing data from hospital records and a systematic review of the literature. The model estimates cost per QALY gained from the National Health Service (NHS) perspective for short- and long-term treatment of infections and service combinations across these.

Results

In short-term treatments, HO was estimated as the most effective (0.7239 QALYs), but at the highest cost (£973). SN was the least costly (£710), producing 0.7228 QALYs. The combination between SN and HO was estimated to produce 0.7235 QALYs at a cost of £841. For long-term treatments, SN was the most effective (0.677 QALYs), costing £2379, while SA was the least costly at £1883, producing 0.666 QALYs. A combination of SA and SN was estimated to produce 0.672 QALYs at a cost of £2128.

Conclusions

SN and SA are cost-effective for short- and long-term treatment of infections, while combining services may represent the second-best alternative for OPAT in the UK.

Community IntraVenous Antibiotic Study (CIVAS): protocol for an evaluation of patient preferences for and cost-effectiveness of community intravenous antibiotic services

INTRODUCTION

Outpatient parenteral antimicrobial therapy (OPAT) is used to treat a wide range of infections, and is common practice in countries such as the USA and Australia. In the UK, national guidelines (standards of care) for OPAT services have been developed to act as a benchmark for clinical monitoring and quality. However, the availability of OPAT services in the UK is still patchy and until quite recently was available only in specialist centres. Over time, National Health Service (NHS) Trusts have developed OPAT services in response to local needs, which has resulted in different service configurations and models of care. However, there has been no robust examination comparing the cost-effectiveness of each service type, or any systematic examination of patient preferences for services on which to base any business case decision.

METHODS AND ANALYSIS

The study will use a mixed methods approach, to evaluate patient preferences for and the cost-effectiveness of OPAT service models. The study includes seven NHS Trusts located in four counties. There are five inter-related work packages: a systematic review of the published research on the safety, efficacy and cost-effectiveness of intravenous antibiotic delivery services; a qualitative study to explore existing OPAT services and perceived barriers to future development; an economic model to estimate the comparative value of four different community intravenous antibiotic services; a discrete choice experiment to assess patient preferences for services, and an expert panel to agree which service models may constitute the optimal service model(s) of community intravenous antibiotics delivery.

ETHICS AND DISSEMINATION

The study has been approved by the NRES Committee, South West-Frenchay using the Proportionate Review Service (ref 13/SW/0060). The results of the study will be disseminated at national and international conferences, and in international journals.

Helping to drive the robustness of preclinical research - the assay capability tool

Numerous articles in Nature, Science, Pharmacology Research and Perspectives, and other biomedical research journals over the past decade have highlighted that research is plagued by findings that are not reliable and cannot be reproduced. Poor experiments can occur, in part, as a consequence of inadequate statistical thinking in the experimental design, conduct and analysis. As it is not feasible for statisticians to be involved in every preclinical experiment many of the same journals have published guidelines on good statistical practice. Here, we outline a tool that addresses the root causes of irreproducibility in preclinical research in the pharmaceutical industry. The Assay Capability Tool uses 13 questions to guide scientists and statisticians during the development of in vitro and in vivo assays. It promotes the absolutely essential experimental design and analysis strategies and documents the strengths, weaknesses, and precision of an assay. However, what differentiates it from other proposed solutions is the emphasis on how the resulting data will be used. An assay can be assigned a low, medium, or high rating to indicate the level of confidence that can be afforded when making important decisions using data from that assay. This provides transparency on the appropriate interpretation of the assay's results in the light of its current capability. We suggest that following a well-defined process during assay development and use such as that laid out within the Assay Capability Tool means that whatever the results, positive or negative, a researcher can have confidence to make decisions upon and publish their findings.

The success of rectus and gracilis muscle flaps in the treatment of chronic pelvic sepsis and persistent perineal sinus: a systematic review

AIM

Chronic pelvic sepsis is a challenging problem, which may require muscle flaps to fill the pelvic cavity. The aim of this systematic review was to determine the relative success of rectus and gracilis flaps used for this purpose.

METHOD

A systematic review was conducted to identify papers that reported the outcome of rectus or gracilis myocutaneous flaps in the treatment of persistent perineal sinuses or chronic pelvic sepsis. Reports of muscle flaps used for reconstruction or treatment of fistula in the absence of chronic sepsis were excluded. A successful outcome was defined as complete perineal healing within 12 months of surgery.

RESULTS

The review identified 19 studies reporting the outcome of 73 rectus and 87 gracilis flaps. Their respective success was 84% and 64%. Heterogeneity of the underlying cases did not allow for direct comparison of the flaps. Full healing of the flaps was generally achieved within 3 months. Donor site morbidity was minimal.

CONCLUSION

The surgical treatment of chronic pelvic sepsis should be tailored to the individual, but the rectus flap has a reasonable success rate with little morbidity.

ACTINOMYCOSIS INFECTION OF THE FINGER

Actinomycosis is a rare cause of infection in the hand. We report a case of actinomycosis infection involving proximal phalanx, with the clinical presentation mimicking that of a bony neoplasm.

Melanoma sentinel node biopsy and prediction models for relapse and overall survival

BACKGROUND

To optimise predictive models for sentinal node biopsy (SNB) positivity, relapse and survival, using clinico-pathological characteristics and osteopontin gene expression in primary melanomas.

METHODS

A comparison of the clinico-pathological characteristics of SNB positive and negative cases was carried out in 561 melanoma patients. In 199 patients, gene expression in formalin-fixed primary tumours was studied using Illumina's DASL assay. A cross validation approach was used to test prognostic predictive models and receiver operating characteristic curves were produced.

RESULTS

Independent predictors of SNB positivity were Breslow thickness, mitotic count and tumour site. Osteopontin expression best predicted SNB positivity (P=2.4 × 10⁻⁷), remaining significant in multivariable analysis. Osteopontin expression, combined with thickness, mitotic count and site, gave the best area under the curve (AUC) to predict SNB positivity (72.6%). Independent predictors of relapse-free survival were SNB status, thickness, site, ulceration and vessel invasion, whereas only SNB status and thickness predicted overall survival. Using clinico-pathological features (thickness, mitotic count, ulceration, vessel invasion, site, age and sex) gave a better AUC to predict relapse (71.0%) and survival (70.0%) than SNB status alone (57.0, 55.0%). In patients with gene expression data, the SNB status combined with the clinico-pathological features produced the best prediction of relapse (72.7%) and survival (69.0%), which was not increased further with osteopontin expression (72.7, 68.0%).

CONCLUSION

Use of these models should be tested in other data sets in order to improve predictive and prognostic data for patients.

Endometrial biopsy: a valuable clinical and research tool in bovine reproduction

Studies of postpartum endometrial physiologic and immune mechanisms in cows are compromised by the difficulty in acquiring tissue of suitable quality and in sufficient quantity (Bos taurus). Endometrial biopsy sampling has attracted concern regarding potential animal ill-health and perturbed subsequent fertility. Here, we describe a method of endometrial biopsy that obtains high-quality tissue samples and does not compromise fertility. Using a Hauptner instrument, endometrial biopsies were taken at 15, 30, and 60 d postpartum from 13 mixed-breed beef cows. The effects of repeat biopsy on health (heart rate, respiration rate, color of mucous membranes, rectal temperature), onset of estrous cyclicity, and first service conception rate were monitored. Extensive daily clinical examinations revealed no signs of ill-health. All cows had resumed estrous cyclicity at 60 d postpartum. A conception rate of 77% was achieved after estrus synchronization and artificial insemination. Each biopsy yielded intact endometrial tissue and nucleic acid suitable for extensive histologic and molecular analysis, respectively. We conclude that when carried out appropriately, bovine endometrial biopsy is a safe and reliable technique for assessing postpartum uterine function or health.

Experience with multiple stent implantations in primary antiphospholipid syndrome in childhood: a case report

The antiphospholipid syndrome (APS) is an autoimmune condition characterized by the persisting presence of antiphospholipid antibodies in association with thrombosis and/or pregnancy morbidity. Primary APS is quite rare in childhood and exact prevalence is not known. However, substantial proportion of thrombotic events in children is being attributed to APS. We herein present a 9-year-old boy presented with impending pericardial tamponade and large pleural effusions likely secondary to transudation of fluid from his gradually developed collateral circulation which was resulted from almost completely occluded vena caval system due to primary APS. He was treated with multiple angioplasty-stenting which offered symptomatic relief and better quality of life. To our knowledge, this is the first reported paediatric case of primary APS presented with extensive occlusive lesions in both caval systems and treated with repeated endovascular stent placements.

Shouldered plates and shats in tension and torsion

Room-temperature and frozen-stress photoelastic tests have been carried out to determine the magnitude, position, and extent of the stress concentrations which occur in the blending radii at the junctions of sections of different widths in symmetrical plates subjected to direct loads.

An empirical equation has been derived from the flat-plate tests which is also applicable to shafts in tension.

Other published data are consisent with the predictions of the empirical equations.

Stress concentration factors for shafts in torsion are lower than in tension.

Comparison of the clock test and a questionnaire-based test for screening for cognitive impairment in Nigerians

BACKGROUND

Since it is projected that by 2020 seventy percent of the elderly will reside in developing countries, a reliable screening method for dementia and cognitive impairment in general in populations with diverse languages, culture, education and literacy will be needed. We sought to determine if the Clock Test, a screening test for dementia, was suitable for use in a Nigerian population.

STUDY DESIGN

Cross-sectional survey of 54 men and 12 women from Northern Nigeria. Researchers administered two dementia screening tools: a questionnaire-based test adapted for use in a Nigerian population and the Clock Test.

RESULTS

Overall, 53.0% of the subjects had an abnormal Clock Test whereas 10.6% of the subjects had an abnormal questionnaire score. Only 9.1% of the subjects had abnormal scores on both tests. Subjects with more schooling had a greater probability of having a positive clock concept (understanding that a circle represented a clock). Of those with more than 6 years of schooling, 91.0% had a positive clock concept. Subjects with a negative clock concept were more likely to have an abnormal Clock Test (93.3%) than a questionnaire (26.6%).

CONCLUSIONS

The main finding of our study was the discrepancy between the results of the Clock Test and the questionnaire. Performance on the Clock Test appeared to have been heavily influenced by education level, indicating the test is not universally applicable across cultures. The questionnaire-based test appears to reduce the effects of illiteracy on assessing dementia in a Nigerian population. Larger studies should be done to control for how education affects the assessment of dementia.

The Unit Strength Concept in the Interpretation of Beam Test Results for Brittle Materials

SYNOPSIS

Brittle materials are usually characterised in terms of the “modulus of rupture” obtained from the results of fracture tests on beam specimens. This is not a fundamental quantity. Alternative quantities (the mean strength of unit volume and of unit area) are introduced which are independent of the size of the specimen and the form of test, which allow the correlation of results from different tests, and which may be validly used in design calculations. After an outline of the necessary theory, the derivation of the two “unit strengths” and their use in correlating test results are illustrated using fracture data from a series of reaction-bonded silicon nitride beams. Minimum values obtained are:- mean uniaxial fracture stress of unit volume, 140 N/mm2per cm3; mean uniaxial fracture stress of unit surface area, 180 N/mm2per cm2.

A means of allowing for the effects of contact friction in the analysis of beam fracture test data is presented. The ignoring of these effects may result in a significant over-estimate of strength. The measured coefficient of friction decreased with increased load intensity.

Real-time imaging of gene promoter activity using an adenoviral reporter construct demonstrates transcriptional dynamics in normal anterior pituitary cells

Although analysis of luciferase activity using luminescence imaging has provided new insights into the dynamic regulation of gene expression in living tIssues, studies in vitro have relied on stably transfected clonal cell lines, limiting the choice of cell type and species, or DNA microinjection, which is arduous and highly selective. We report here the first use of a recombinant adenovirus in which the firefly luciferase reporter gene was regulated by the prolactin gene promoter, to study temporal dynamics of promoter activity. This vector was used to infect the pituitary GH3 cell line, and also primary cultures of Syrian hamster pituitary cells. We show that adenovirally transduced cells retained normal regulation of the promoter-reporter transgene by appropriate signals. Furthermore, microscopic imaging studies indicated that both clonal and primary pituitary cells were transduced efficiently, giving readily detectable luminescence signals in real-time over long periods. Finally, analysis of single-cell expression patterns indicated that prolactin promoter activity was highly dynamic with pulses in gene expression, revealing that the transcriptional instability seen in clonal cells is a feature of normal pituitary cells. Adenoviral vectors offer a valuable tool for studies of gene regulation where conventional transgenesis and clonal cell lines are not available.

Fringe modulation of Jagged1-induced Notch signaling requires the action of beta 4galactosyltransferase-1

Fringe modulates Notch signaling resulting in the establishment of compartmental boundaries in developing organisms. Fringe is a beta 3N-acetylglucosaminyltransferase (beta 3GlcNAcT) that transfers GlcNAc to O-fucose in epidermal growth factor-like repeats of Notch. Here we use five different Chinese hamster ovary cell glycosylation mutants to identify a key aspect of the mechanism of fringe action. Although the beta 3GlcNAcT activity of manic or lunatic fringe is shown to be necessary for inhibition of Jagged1-induced Notch signaling in a coculture assay, it is not sufficient. Fringe fails to inhibit Notch signaling if the disaccharide generated by fringe action, GlcNAc beta 3Fuc, is not elongated. The trisaccharide, Gal beta 4GlcNAc beta 3Fuc, is the minimal O-fucose glycan to support fringe modulation of Notch signaling. Of six beta 4galactosyltransferases (beta 4GalT) in Chinese hamster ovary cells, only beta 4GalT-1 is required to add Gal to GlcNAc beta 3Fuc, identifying beta 4GalT-1 as a new modulator of Notch signaling.

Modification of epidermal growth factor-like repeats with O-fucose. Molecular cloning and expression of a novel GDP-fucose protein O-fucosyltransferase

The O-fucose modification is found on epidermal growth factor-like repeats of a number of cell surface and secreted proteins. O-Fucose glycans play important roles in ligand-induced receptor signaling. For example, elongation of O-fucose on Notch by the beta1,3-N-acetylglucosaminyltransferase Fringe modulates the ability of Notch to respond to its ligands. The enzyme that adds O-fucose to epidermal growth factor-like repeats, GDP-fucose protein O-fucosyltransferase (O-FucT-1), was purified previously from Chinese hamster ovary (CHO) cells. Here we report the isolation of a cDNA that encodes human O-FucT-1. A probe deduced from N-terminal sequence analysis of purified CHO O-FucT-1 was used to screen a human heart cDNA library and expressed sequence tag and genomic data bases. The cDNA contains an open reading frame encoding a protein of 388 amino acids with a predicted N-terminal transmembrane sequence typical of a type II membrane orientation. Likewise, the mouse homolog obtained from an expressed sequence tag and 5'-rapid amplification of cDNA ends of a mouse liver cDNA library encodes a type II transmembrane protein of 393 amino acids with 90.4% identity to human O-FucT-1. Homologs were also found in Drosophila and Caenorhabditis elegans with 41.2 and 29.4% identity to human O-FucT-1, respectively. The human gene (POFUT1) is on chromosome 20 between PLAGL2 and KIF3B, near the centromere at 20p11. The mouse gene (Pofut1) maps near Plagl2 on a homologous region of mouse chromosome 2. POFUT1 gene transcripts were expressed in all tissues examined, consistent with the widespread localization of the modification. Expression of a soluble form of human O-FucT-1 in insect cells yielded a protein of the predicted molecular weight with O-FucT-1 kinetic and enzymatic properties similar to those of O-FucT-1 purified from CHO cells. The identification of the gene encoding protein O-fucosyltransferase I now makes possible mutational strategies to examine the functions of the unusual O-fucose post-translational modification.

Mechanical strength testing of compacted powders

Alternative test specimens for the determination of the fracture stress of brittle materials (eg. compacted powders) are described and discussed, and a statistical approach to the processing of strength test data is outlined.

Independent Lec1A CHO glycosylation mutants arise from point mutations in N-acetylglucosaminyltransferase I that reduce affinity for both substrates. Molecular consequences based on the crystal structure of GlcNAc-TI

A key enzyme in regulating the maturation of N-linked glycans is UDP-N-acetylglucosamine:alpha-3-D-mannoside beta-1,2-N-acetylglucosaminyltransferase I (GlcNAc-TI, EC 2.4.1.101). Lec1 CHO cells lack GlcNAc-TI activity and synthesize only the oligomannosyl class of N-glycans. By contrast, Lec1A CHO mutants have weak GlcNAc-TI activity due to the reduced affinity of GlcNAc-TI for both the UDP-GlcNAc and Man(5)GlcNAc(2)Asn substrates. Lec1A CHO mutants synthesize hybrid and complex N-glycans, albeit in reduced amounts compared to parental CHO cells. In this paper, we identify two point mutations that gave rise to the Lec1A phenotype in three independent Lec1A CHO mutants. The G634A mutation in Lec1A.2C converts an aspartic acid to an asparagine at amino acid 212, disrupting a conserved DXD motif (E(211)DD(213) in all GlcNAc-TIs) that makes critical interactions with bound UDP-GlcNAc and Mn(2+) ion in rabbit GlcNAc-TI. The C907T mutation in Lec1A.3E and Lec1A.5J converts an arginine conserved in all GlcNAc-TIs to a tryptophan at amino acid 303, altering interactions that are important in stabilizing a critical structural element in rabbit GlcNAc-TI. Correction of each mutation by site-directed mutagenesis restored their GlcNAc-TI activity and lectin binding properties to parental levels. The effect of the two amino acid changes on GlcNAc-TI catalysis is discussed in relation to the crystal structure of rabbit GlcNAc-TI complexed with manganese and UDP-GlcNAc.

Point mutations identified in Lec8 Chinese hamster ovary glycosylation mutants that inactivate both the UDP-galactose and CMP-sialic acid transporters

Nucleotide-sugar transporters (NSTs) are critical components of glycosylation pathways in eukaryotes. The identification of structural elements that are involved in NST functions provides an important task. Chinese hamster ovary glycosylation mutants defective in nucleotide-sugar transport provide access to inactive transporters that can define such structure/function relationships. In this study, we have cloned the hamster UDP-galactose transporter (UGT) and identified defects in UGT gene transcripts from nine independent Chinese hamster ovary mutants that belong to the Lec8 complementation group. Reverse transcription polymerase chain reaction with primers that span the UGT open reading frame showed that three Lec8 mutants express a full-length open reading frame, while six Lec8 mutants predominantly express truncated UGT gene transcripts. Sequencing identified different single or triplet nucleotide changes in full-length UGT transcripts from three of the mutants. These mutations translate into three different amino acid changes at positions that are highly conserved in all the known mammalian NSTs. Transfection of a cDNA encoding either of the mutations Delta serine 213 or G281D failed to correct the UDP-galactose transport defect in Lec8 transfectants. Most importantly, introducing these same mutations into the homologous region of the murine CMP-sialic acid transporter caused inactivation of this transporter. Thus, identifying point mutations that inactivate UGT in Lec8 mutants resulted in the discovery of amino acids that are critical to the activity of both UGT and CST, the two most divergent mammalian NSTs.

Role of the Lewis(x) glycan determinant in corneal epithelial cell adhesion and differentiation

In this study we demonstrate that in corneal epithelium there is cell-cell contact-regulated expression of a 145-kDa glycoprotein (GP) bearing the glycan determinant Lewis(x) (Le(x)) (Galbeta(1,4)[Fucalpha(1,3)]GlcNAc). This glycoprotein (Le(x)-GP) was expressed in confluent/contact-inhibited cultures but not in sparse cultures of corneal epithelium. In contrast, a 135-kDa glycoprotein bearing precursor, unfucosylated, lactosamine-containing glycans (Galbeta1-4GlcNAcbeta1-R) was expressed in sparse cultures. Immunofluorescence staining and confocal microscopy of confluent cultures revealed that in corneal epithelium, Le(x) antigen is located in high density at sites of cell-cell adhesion. In in vitro cell-cell adhesion assays, anti-Le(x), but not anti-sialyl-Le(x) monoclonal antibodies, inhibited the formation of corneal epithelial cell-cell adhesion. Also, when added to confluent cultures, antibodies to Le(x) disrupted the monolayer and caused tightly packed polygonal cells to round up. Analysis of the expression of Fut genes that encode alpha-1,3-fucosyltransferases, the enzymes that generate the Le(x) determinant, revealed that confluent/contact-inhibited cultures of rabbit corneal epithelium contain markedly elevated levels of Fut4 and Fut3/5/6 gene transcripts compared with sparse cultures. These data suggest that the Fut4 and Fut3/5/6 genes are targets of cell-cell contact-regulated signals and that Fut gene products direct cell-cell contact-associated expression of Le(x) on the Le(x)-GP in corneal epithelium. Immunohistochemical analysis revealed that the expression of Le(x) antigen in the epithelium of adult and developing corneas is related to the stage of differentiation of the cells. Although early differentiated cells robustly expressed Le(x), relatively undifferentiated cells did not, and the expression level was relatively low in terminally differentiated cells. Overall, these data provide evidence that a Le(x)-bearing glycoprotein plays a role through the Le(x) determinant in corneal epithelial cell-cell adhesion, and these data suggest that Le(x)-mediated cell-cell interactions contribute to mechanisms that mediate corneal epithelial cell differentiation.

Novel mimics of sialyl Lewis X: design, synthesis and biological activity of a series of 2- and 3-malonate substituted galactoconjugates

A series of potent inhibitors of P-selectin as potential anti-inflammatory agents is reported. These compounds are derivatives of galactocerebrosides bearing a malonate side chain in positions 2 and 3 of the galactose moiety. Based on the binding mode of sialyl Lewis X, the two acidic groups of the malonate are designed to form ionic interactions with two important lysines in the active site of P-selectin, Lys113 and Lys111. On the other hand, the 4- and 6-hydroxy groups on the galactose ring are arranged to chelate the calcium ion in the P-selectin active site. The synthesis and the biological activity of this series of compounds are described. Lead compounds having a greater potency than sialyl Lewis X are identified.

Chinese hamster ovary (CHO) cells may express six beta 4-galactosyltransferases (beta 4GalTs). Consequences of the loss of functional beta 4GalT-1, beta 4GalT-6, or both in CHO glycosylation mutants

Six beta4-galactosyltransferase (beta4GalT) genes have been cloned from mammalian sources. We show that all six genes are expressed in the Gat(-)2 line of Chinese hamster ovary cells (Gat(-)2 CHO). Two independent mutants termed Pro(-)5Lec20 and Gat(-)2Lec20, previously selected for lectin resistance, were found to have a galactosylation defect. Radiolabeled biantennary N-glycans synthesized by Pro(-)5Lec20 were proportionately less ricin-bound than similar species from parental CHO cells, and Lec20 cell extracts had a markedly reduced ability to transfer Gal to GlcNAc-terminating acceptors. Northern blot analysis revealed a severe reduction in beta4GalT-1 transcripts in Pro(-)5Lec20 cells. The Gat(-)2Lec20 mutant expressed beta4GalT-1 transcripts of reduced size due to a 311-base pair deletion in the beta4GalT-1 gene coding region. Northern analysis with probes from the remaining five beta4GalT genes revealed that Gat(-)2 CHO and Gat(-)2Lec20 cells express all six beta4GalT genes. Unexpectedly, the beta4GalT-6 gene is not expressed in either Pro(-)5 or Pro(-)5Lec20 cells. Thus, in addition to a deficiency in beta4GalT-1, Pro(-)5Lec20 cells lack beta4GalT-6. Nevertheless, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry data of N-glycans released from cellular glycoproteins showed that both the beta4GalT-1(-) (Gat(-)2Lec20) and beta4GalT-1(-)/beta4GalT-6(-) (Pro(-)5Lec20) mutants have a similar Gal deficiency, affecting neutral and sialylated bi-, tri-, and tetraantennary N-glycans. By contrast, glycolipid synthesis was normal in both mutants. Therefore, beta4GalT-1 is a key enzyme in the galactosylation of N-glycans, but is not involved in glycolipid synthesis in CHO cells. beta4GalT-6 contributes only slightly to the galactosylation of N-glycans and is also not involved in CHO cell glycolipid synthesis. These CHO glycosylation mutants provide insight into the variety of in vivo substrates of different beta4GalTs. They may be used in glycosylation engineering and in investigating roles for beta4GalT-1 and beta4GalT-6 in generating specific glycan ligands.

Syringohydromyelia following meningomyelocele surgery--role of metrizamide myelography and computed tomography

Five children developed symptoms attributable to syringohydromyelia several years following neonatal surgery for lumbosacral meningomyelocele. Metrizamide injection followed by computed tomography (CT) was performed in all five patients. In two patients, there was direct opacification of both the subarachnoid space and the syringohydromyelia. In a further two patients, delayed CT demonstrated late opacification of the central cavity from contrast introduced into the subarachnoid space. In the fifth patient via a suboccipital puncture, there was fortuitous filling of a caudally displaced fourth ventricle communicating with a central cavity within the cord, but there was no visualization of the subarachnoid space. Surgery with decompression and plugging of the obex halted the progression of the disease in all the patients.

Interaction of Escherichia coli hemolysin with biological membranes. A study using cysteine scanning mutagenesis

Escherichia coli hemolysin (HlyA) is a membrane-permeabilizing protein belonging to the family of RTX-toxins. Lytic activity depends on binding of Ca2(+) to the C-terminus of the molecule. The N-terminus of HlyA harbors hydrophobic sequences that are believed to constitute the membrane-inserting domain. In this study, 13 HlyA cysteine-replacement mutants were constructed and labeled with the polarity-sensitive fluorescent probe 6-bromoacetyl-2-dimethylaminonaphthalene (badan). The fluorescence emission of the label was examined in soluble and membrane-bound toxin. Binding effected a major blue shift in the emission of six residues within the N-terminal hydrophobic domain, indicating insertion of this domain into the lipid bilayer. The emission shifts occurred both in the presence and absence of Ca2(+), suggesting that Ca2(+) is not required for the toxin to enter membranes. However, binding of Ca2(+) to HlyA in solution effected conformational changes in both the C-terminal and N-terminal domain that paralleled activation. Our data indicate that binding of Ca2(+) to the toxin in solution effects a conformational change that is relayed to the N-terminal domain, rendering it capable of adopting the structure of a functional pore upon membrane binding.

Illness perceptions and mood in chronic fatigue syndrome

BACKGROUND

Individual beliefs and cognitions may affect adjustment to chronic fatigue syndrome (CFS) and illness perceptions, in particular, have been reported to correlate with both disability and psychological adjustment to CFS in self-diagnosed cases.

OBJECTIVES

The aim of the present study was to examine these relationships in a clinic sample of CFS patients assessed by both a physician and psychiatrist.

METHOD

A sample of 173 patients referred to a multidisciplinary CFS clinic and fulfilling current operational criteria for CFS [Ann Intern Med 121 (1994) 953; J R Soc Med 84 (1991) 118.] were randomly selected from the clinic database and surveyed with the Hospital Anxiety and Depression scale, Fatigue Questionnaire and Illness Perceptions Questionnaire [J Psychosom Res 37 (1993) 147; Psychol Health 11 (1996) 431; Acta Psychiatr Scand 67 (1983) 361.].

RESULTS

A total of 126 patients responded (73% response rate). The illness perception components studied were consequences (of illness), illness identity, causes (of illness), the ability to control/cure the illness and (expected) timeline of the illness. These components accounted for 15%, 28% and 30% of the variance in levels of fatigue, depression and anxiety, respectively. Two of the illness perception components (consequences and illness identity) were stronger predictors of fatigue score than mood scores.

CONCLUSIONS

These findings confirmed in a clinical sample that illness perceptions are associated with variation in both disability and psychological adjustment in CFS. Illness perceptions may have an important and long-lasting effect on adaptation to CFS, and it is necessary to have a greater understanding of their role in order to tailor effective interventions for the condition.